SinkholeOdds

Sinkhole risk in Charlevoix County, MI: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock
33%
At or near the surface
11%
Buried under cover
22%

What this means before you buy

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 137 of Charlevoix County's 416 square miles on soluble rock, 45 of them with the rock at or near the surface. With about 26,105 residents (63 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 625 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and why the 22% under cover still counts.

Counties around Charlevoix County

The nearest county rated sinkhole country is Emmet County, MI, about 27 miles east, close enough that the same rock may run under the county line. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

The rock underneath

The largest mapped soluble unit here is the Traverse Group (limestone), Middle Devonian in age, covering about 22% of the county. Next is the Detroit River Group at 6%.

6% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

The county also lies over the Michigan Basin; Ohio Basin; Appalachian Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Michigan

Charlevoix County ranks 1 of 83 in Michigan for soluble rock at the surface, and sits above 68% of US counties on that measure.